Video: Bird flu in U.S. not deadly to humans

WASHINGTON — Scientists have discovered the presence of a strain of bird flu in wild mute swans in Michigan — but testing ruled out it being the worrisome, highly pathogenic form of the virus which has spread throughout much of the rest of the world and killed at least 138 people worldwide, officials at the Agriculture Department said Monday.

“This is not the highly pathogenic avian influence virus that has spread through much of other parts of the world,” said Ron DeHaven, administrator of USDA’s Animal and Plant Health Inspection Service.

“We do not believe this virus represents a risk to human health,” he declared.

Routine tests on two seemingly healthy wild mute swans in Michigan suggest they might have the H5N1 virus; confirmatory tests are under way.

Still, if it is the low-pathogenic version of H5N1, it would be the first time in 20 years that scientists have found even that version of the H5N1 virus in the United States, USDA officials said. A similar low-pathogenic version of the virus was found in Canada last year.

Despite the lack of human risk, federal officials said they were announcing the apparent discovery as a sign of openness about the $29 million effort to check for signs that H5N1 is posing a renewed threat to U.S. birds.

“We remain vigilant and prepared,” said Dr. William Raub, science adviser to the Department of Health and Human Services.

The deadly version of the H5N1 virus has killed at least 138 people worldwide since beginning its global march in late 2003. But virtually all caught the virus from close contact with sick birds or their droppings.

Scientists had feared that the deadly form of the virus would reach North America — in birds — sometime this year. Just last week, the U.S. expanded monitoring of wild migratory birds throughout the nation, to check for early signs.

Health officials are closely watching H5N1 for fear the virus eventually could mutate into a strain that could spread easily from person-to-person, possibly sparking a worldwide epidemic. No one knows how likely that is to happen, and specialists agree that the risk doesn’t jump even if a few infected birds are found to have entered the U.S.

Still, even the low-pathogenic H5N1 requires monitoring, because it has the potential to mutate into the highly pathogenic form — the kind that rapidly kills birds, especially poultry. If it were found in the U.S., that would trigger additional security steps to prevent wild birds from infecting commercial poultry flocks.